Sunday, December 03, 2006

What is DHCP,NetBIOS Name,WINS,DNS?

Dynamic Host Configuration Protocol(DHCP):DHCP is a TCP/IP standard designed to reduce the complexity of administering Address configurations by using a Server. The DHCP server centralizes and manages the allocation of TCP/IP configuration by automatically assigning IP Addresses,Subnet Mask and Default gateway to computers that have been configured to use DHCP.

Whenever a DHCP server receives request from a DHCP client then DHCP server selects an IP Address from a pool of addresses defined in database then offers it to the client for a specified period of time. So client receives valid IP Address.

Suppose we manually configuring IP Addresses,Subnet mask and Gateway. Then entering an invalid IP Address or IP Address currently in use can result in network problems. Entering an incorrect Subnet mask can cause communication problems with other networks.

NetBIOS Name:It is the computer or host name assigned during installation. The Registry stores this name as an entry. We can change this name through the network program in control panel. The name can be 15 characters in length and we can add a 16 character to the name to designate the application that registered the name.

Windows Internet name Service(WINS):WINS registers NetBIOS computer names and resolve them to IP Addresses. The database of WINS is DYNAMIC. WINS is designed for Microsoft operating systems only.

If the WINS client initiates a NetBIOS command to communicate with another host then the name query request is sent to WINS server. If the WINS server finds a NetBIOS name/IP address mapping for a host in its database then it returns the destination host's IP Address to the WINS client.

Domain Name System(DNS):DNS is a system for naming computers and network services. These names are organized into a hierarchy of domains. DNS is used in TCP/IP networks,such as the internet,to locate computers and services through user friendly names. When a user enters a DNS name in an application then DNS services can resolve the name to an IP Address.

Suppose there is a mail server on a network. It has it's own numeric Address. For most users it is difficult to remember the numeric address of the server. Then DNS system names this computer with a user friendly name like example.companymail.com. Any one can remember this type of user friendly name very easily. But computers communicate over network by using numeric Addresses. So DNS services can resolve this user friendly name to it's numeric Address.

DNS uses a client server model in which DNS servers(Name servers) contain information about the DNS database and make this information available to clients(Resolvers).

In brief DNS resolves internet names to IP Addresses. DNS database is static and manually updated whenever a new host is added or an existing host is moved to another subnet. DNS is designed for both Microsoft operating systems and Non Microsoft operating systems such as MainFrames running TCP/IP and UNIX based computers.

Note: Articles on Windows NT,Windows 2000 Server,Windows 2003 Server will come soon on my blog under the same NETWORKING section.